The present invention relates to latches that are operated by push button assemblies of the type having depressible push buttons supported by housings. More particularly, the present invention relates to a linkage assembly having a frame that is connectable to the housing of a push button assembly and that pivotally supports a pair of arms that are connectable to one or more links for operating one or more latches in response to movement of a push button actuator along a path of movement that is defined by the housing of the push button assembly.
The present invention provides an improved linkage assembly that can be substituted for the linkage assembly that is disclosed in FIGS. 12-23 of the Eberhard Patent to perform the same functions as are performed by the linkage assembly disclosed in FIGS. 12-23 of the Eberhard Patent. The Eberhard Patent's discussion of the uses to which the linkage assembly of FIGS. 12-23 can be put is equally applicable to the linkage assembly of the present invention.
The present invention provides an improved linkage assembly that also can be substituted for the linkage assembly that is disclosed in U.S. Pat. No. 6,231,091 issued May 15, 2001 to Gleason et al entitled CONTROL MECHANISM FOR OPERATING A LATCH (referred to herein as the “Tri/Mark Patent”) to perform the same functions as are performed by the linkage assembly disclosed in the Tri/Mark Patent, the disclosure of which is incorporated herein by reference. The Tri/Mark Patent's discussion of the uses to which the linkage assembly disclosed therein can be put is equally applicable to the linkage assembly of the present invention.
The linkage assemblies of the Eberhard Patent and the Tri/Mark Patent each include a frame that is designed to be installed on, or otherwise connected to, a housing of a push button assembly of the type having a housing that supports a push button actuator for sliding movement along a path of movement defined by the housing. The frame of the linkage assembly supports first and second arms for pivotal movement about first and second axes, respectively, that are located on opposite sides of the path of movement of the actuator. The arms have outer end regions that are connectable to links that operate remotely located latches, and inner end regions that define edge surfaces that are engaged by the actuator when the actuator moves along the path of movement.
Another characteristic that is shared by the linkage assemblies of the Eberhard and Tri/Mark Patents is that the first and second arms of each of these linkage assemblies move independently with respect to each other: there is no separate element—indeed, nothing at all—that coordinates the movement of the first and second arms of either of these linkages. Inasmuch as neither of these linkage assemblies is provided with any means for coordinating the movement of the first and second arms thereof, there likewise is nothing to ensure that, at the completion of operation of the push button actuator, both (or even one) of the first and second arms returns to its normal, non-operated position. Thus, at the completion of an unlatching movement of both arms, it is quite possible that only one of the arms may return fully to its nonoperated position, or that neither of the arms may return fully to its non-operated position. The result of this uncoordinated return movement of the arms may be that, when the push button actuator is depressed to engage and pivot the arms, one of the arms may be engaged by the actuator well in advance of when the other arm is engaged by the actuator.
Inasmuch as the linkage assemblies of the Eberhard and Tri/Mark Patents are intended to operate in a manner that provides coordinated pivoting of the arms of these assemblies in unison to effect concurrent operation of the latches that are link-connected to these arms, the fact of the matter is that these neither of these linkage assemblies includes a mechanical device for ensuring that the arms move in unison. If the independently movable arms fail to move in unison in a coordinated manner, this can result in inconsistent operation that may bring with it impositions of larger than intended forces on the elements of the linkage assemblies that may eventually cause binding, jamming, wear and/or premature operational failure.
The absence of any arm-interconnecting element in the linkage assemblies of the Eberhard and Tri/Mark Patents to coordinate the movements of the arms of these assemblies has presented a dilemma to designers that has not been easy to resolve without significantly increasing the overall dimensions of the linkage assemblies. Because customers who purchase these very compactly designed linkage assemblies often use these assemblies in tight quarters in close juxtaposition to other mechanical components and, in some instances, enclose these assemblies with closely fitted covers, it is important that any design changes that are made in an effort to enhance the performance of these assemblies not cause the improved linkage assemblies to occupy significantly more space or to assume significantly different configurations that prevent the improved linkage assemblies from being substituted for linkage assemblies of the type disclosed in the Eberhard and Tri/Mark Patents.
Because the linkage assemblies of the Eberhard and Tri/Mark Patents are already quite compact and already are designed to occupy a minimum of space, adding components to these assemblies to coordinate the movement of the first and second arms of these assemblies has provided a daunting design challenge. While a number of design approaches have been tried in an effort to coordinate the movement of the arms of these linkage assemblies, one approach after another has had to be rejected because it caused an unacceptable increase in the space occupied by the linkage assembly, or because it caused an unacceptable change in the dimensions or configuration of the linkage assembly, or, quite importantly, because it failed to provide adequate arm movement (in response to about a half inch or less of travel of a push button actuator) to move latch operating links (that are connected to the arms and to latches that are to be operated in response to depression of a push button actuator) sufficiently to operate the latches that are intended to be operated by the linkage assembly.
Still another drawback of the linkage assemblies disclosed in the Eberhard and Tri/Mark Patents has been the absence of a single element within these assemblies to which an emergency release cable can be connected to enable these linkages to be operated from inside a tonneau covers or from inside large tool boxes or other enclosures on which these linkage assemblies may be installed. If these linkage assemblies could be provided with an element that coordinates the pivotal movement of the arms to ensure that their “operating” and “return” movements take place concurrently and in unison, perhaps an emergency release cable could be attached to the arm-movement-coordinating element to provide a way in which a person trapped within the confines of a tonneau cover, or tool box, or other latched enclosure could release the latches thereof to escape.